1. Field of the Invention.
The present invention relates to method and apparatus for applying viscous materials to curved surfaces generally and, more particularly, but not by way of limitation, to novel such method and apparatus which are particularly useful in the application of drywall paste and similar viscous materials to curved surfaces.
2. Background Art.
A need exists for method and apparatus for applying drywall paste and similar viscous materials to curved surfaces, which are quickly and easily employed.
A number of prior devices have been developed to address the problem of applying plaster, cement, and/or paste materials to curved surfaces. For example, U.S. Pat. Nos. 952,971, issued Mar. 22, 1910, to Wolary et al.; 1,067,301, issued Jul. 15, 1913, to Bricker; 1,083,099, issued Dec. 30, 1913, to Howg; 1,743,704, issued Jan. 14, 1930, to Boux; and 2,947,017, issued Aug. 2, 1960, to Dybdahl, all describe trowel-type implements having blades which are selectively fixed to finish a concave or convex surface. While most of these devices are adjustable, once adjusted, the blades can be used for only one particular curve and the shapes of the blades cannot be changed without time consuming mechanical adjustments. The blades are unsuitable for compound curved surfaces where the surface may change from convex to concave or from convex to flat, for example. Also, the mechanically adjusted devices require more complicated clean up, maintenance, and lubrication.
In the automobile body repair field, small flexible tools have been developed for applying plastic filler materials, such as described in U.S. Pat. Nos. 3,341,878, issued Sep. 19, 1967, and 4,631,019, issued Dec. 23, 1986. Both of the devices described are intended for small intricate auto body work and have fingertip grips for grasping and bending the blades of the tools to conform to the surfaces being filled. Neither tool is designed to move and spread large amounts of viscous material such as drywall compound plaster.
Because of the lack of method and apparatus for applying viscous materials such as drywall paste to curved surfaces, the conventional method of doing so it to use a straight blade and in the case of a vertical column, for example, draw it horizontally around the column. This technique is somewhat limited and is difficult to apply when compound surfaces are involved.
A further disadvantage of conventional drywall finishing blades is that they have a single, centrally mounted handle for one-handed use. Such blades tend to leave ripples in the joint compound because the ends of the blades are free to twist back and forth. Also these blades are relatively small, about 10 to 14 inches wide, which means more passes, more work, and more touch-ups.
Accordingly, it is a principal object of the present invention to provide method and apparatus for applying viscous materials to curved surfaces that are quickly and easily employed.
It is a further object of the invention to provide such apparatus that can accommodate different curved surfaces without mechanical adjustment.
It is an additional object of the invention to provide such apparatus that is economically constructed.
Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.